| Description and Operation The Auxiliary Warning System (AWS) comprises a number of sensors and transducers, a display with electronic control module and a sub‐module to measure the currents in vehicle lamp circuits. The display assembly is located in the instrument panel, adjacent to the steering wheel in a recessed aperture to prevent reflections. The display is partitioned in half by the bezel – the upper half of the display consists of a car outline with door ajar and lamp failure indication, the lower half of the display has seven warning lamps. Additionally, an eighth warning lamp is located in the cluster itself. When the ignition is turned on a bulb function test illuminates the warning symbols for five seconds and then extinguishes them if there are no warnings. The brake light warning lamps stay illuminated after ignition‐on until the brake pedal is depressed. Door/Tailgate/Luggage Compartment Lid Ajar (Five Warnings) The common door ajar switch, which is mounted in each door lock assembly, consists of a single pair of normally‐closed contacts which are shared with the central locking system. The switch is closed only when the door is fully shut, when it presents a safe condition to the control assembly. If the door is open or shut onto the first latch position, the contacts will be open and present an alarm condition to the control assembly. Lamp Failure (Four Warnings) The lamp failure warnings are controlled by a sub‐module that measures the currents in the (dipped) headlights, sidelights, and brake lights when these are turned on and warn of any blown bulbs by a warning symbol in each corner of the car outline. The car outline is illuminated only when one or more of the above warnings are also illuminated. The sub‐module is located behind the left‐hand side lower crash pad. Service Interval This indicator, which consists of a spanner symbol, illuminates when a predefined distance has been covered or time elapsed since the last vehicle service. The approximate distances/times for the two types of engine are as follows: - 15000 km/358 days for Zeta
- 9600 km/358 days for Diesel
The time counter is battery fed so updates regardless of ignition status. In the event of battery disconnection both time and distance counter values are preserved in non‐volatile (E2PROM) memory. The counters (and lamp, if illuminated) are reset by a button in the glove compartment which must be depressed for four seconds with the ignition on. The distance counter is driven by the vehicle speed sensor which produces a square‐wave output with one pulse every 20 cms (5000 pulses/km). Ice Warning (Two Warnings) This warning consists of two snowflakes – one orange, the other red. The orange warning illuminates when the outside air temperature is between 1°C and 4°C. The red warning illuminates when the outside air temperature falls below 1°C. In vehicles not fitted with a stand‐alone trip computer, the signal from the air temperature sensor is taken to the control assembly which illuminates the warning lamps. Negative transitions are displayed immediately, positive transitions are displayed only once a higher temperature and vehicle speeds above 5 mph have both been registered for 10 secs. Thus a fast change from ‐1°C to +6°C whilst moving will cause a change from red to orange after 10 secs followed by the orange going out after a further 10 secs. Air Temperature Sensor The low air temperature sensor contains a negative temperature coefficient thermistor. The resistance seen by the control assembly decreases as temperature increases. In view of the small currents in the sensor (necessary to prevent self‐heating) a local earth is not used and both terminals of the sensor are returned to the control assembly. Brake Pad Wear This warning illuminates when one or more of the (disc) brake pads wears low. Drum brakes are not included. The sensors are small wire loops embedded in the the inner pads of each pair of disc brake pads. When a pad wears down, the wire loop is severed and the appropriate warning is generated. Low Fuel This warning illuminates when the remaining fuel in the tank reaches approximately eight litres, corresponding to the top of the red section on the fuel gauge. The circuit takes an analogue input from the tank sender. In common with the other dynamic fluid level indicators, this input is ”anti‐surged" by the electronics to help prevent erroneous warnings. Low Coolant This warning indicates when engine coolant level is low. The circuit takes a digital input from the coolant level sensor. In common with other dynamic fluid level indicators, this input is ”anti‐surged" by the electronics to help prevent erroneous warnings. The low coolant sensor is a reed switch incorporated into the degas bottle. The switch is activated by a magnetic float. The switch is open when the level is low. Low Screen Washer Fluid This warning indicates when the screen washer fluid level is low. The circuit takes a digital input from the washer bottle level sensor. In common with other dynamic fluid level indicators, this input is ”anti‐surged" by the electronics to help prevent erroneous warnings. The low screen washer fluid level sensor is a reed switch incorporated into the washer bottle. The switch is activated by a magnetic float. The switch is open when the level is low. Low Oil The warning is illuminated when the oil level is low. The warning lamp is located in the cluster and depicts a tray of liquid with a dipstick laying in it. This is a non‐dynamic system, i.e. the oil level sensor is interrogated only at ignition on. To compensate for oil drainback, the oil level sensor is interrogated only if a predefined time (30 secs if lamp was on or 3 mins if lamp was off) has elapsed since the ignition was keyed off. If the ignition is keyed on within that time, the previous status is displayed. On diesel‐engined vehicles there is no provision for oil level sensing and consequently the warning lamp is omitted. The low oil sensor consists of a self‐righting float in a metal cage. The sensor is screwed into a boss on the oil pan such that the float is just immersed when the oil is at the correct level. When the oil level is low, the float rests on the bottom of this cage and a circuit is made via contacts on the float. Interface Module The interface module performs various tasks in different systems, as follows: Provides an audible beep tone for the: - Trip computer low distance to empty warnings
- Trip computer button press acknowledgement
Operates the brake interlock system by: - Monitoring the ignition switch position
- Checking if the brake pedal is pressed
- Checking if the shift lever is still in park
- Driving the release solenoid
Provides a signal to central timer to generate a chime for the: - Not in park and door ajar warnings
Manages the overdrive cancel system by: - Converting the momentary action of the overdrive cancel switch to a toggle action
- Providing the correct signal levels to the EEC IV module
- Synchronising the EEC IV signal to the overdrive cancel lamp signal
- Driving the overdrive cancel lamp
- Monitoring the light switch to dim the overdrive cancel lamp drive as required
Manages the performance/economy lamp by: - Monitoring the performance/economy switch
- Driving the performance/economy lamp
- Monitoring the light switch to dim the performance/economy lamp drive as required
Manages the cruise control lamp by: - Monitoring the cruise control lamp request signal line
- Driving the cruise control lamp
- Monitoring the light switch to dim the cruise control lamp drive as required
Central Timer The central timer, also known as the delay/warning control assembly, has two basic groups of functions, the first group controls the chime warning for the following: - Door ajar with lights on.
- Key in ignition with door open.
- Door open when not in park.
- Seat belt not engaged.
The second group controls the time delay for the following: - Windscreen wipers.
- Heated windows.
- Interior lights.
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